The Blue Boyis an oil painting by Thomas Gainsborough. Perhaps Gainsborough's most famous work, it is thought to be a portrait of Jonathan Buttall (1752–1805), the son of a wealthy hardware merchant, although this has never been proven. It is an historical costume study as well as a portrait: the youth in his 17th-century apparel is regarded as Gainsborough's homage to Anthony Van Dyck, and in particular is very close to Van Dyck's portrait of Charles II as a boy.